1. Field of the Invention
In the field of transporting and processing information processing data, several mechanisms must be taken into account in order to guarantee security: authentication of individuals and of data, and enciphering and deciphering confidential data. For a certain number of years, microcircuit cards, commonly called chip cards or smart cards, have been used to implement these mechanisms. These cards are provided with a microprocessor which, in accordance with a program contained in ROM, controls the access to the information stored in a programmable memory.
2. Description of the Invention
The chip card is a portable object that can be issued to an individual or a group of individuals. To gain access to the information memorized in the memory of the microcircuit, the user or users of the card must necessarily be authenticated. To do so, a first method comprises asking the user to type in a holder code (or xe2x80x9cPINxe2x80x9d, for Personal Identification Number) on a key board, and transmitting this code to the microcircuit on the card. The card compares it with a reference code, and if they are the same, the user is authorized to access the information on the card. Because there are so many applications using microcircuit cards, there are manifold holder codes. The users often have difficulty remembering several such codes. One solution is to identify the users using a biometric impression, or print. This impression may be of the fingerprint, the retina, or the particular form of a signature. Hence users no longer have to remember their holder code; they present their finger or subject their eye to analysis by a camera, or they write their signature manually on a touch-sensitive display.
This solution has one disadvantage in terms of security. The print or impression, whatever its nature, is perceived by an appliance, and the signals are communicated to the card by an electrical connection. A criminal can put a bug on this connection and thus record the characteristic signals of the print of an individual. Having done so, he can reproduce these signals and pass as that individual. The problem is due to the fact that a biometric print is immutable and its value remains fixed. Conversely, holder codes can be changed when they are memorized in the programmable memory of a card, but as has just been explained, this solution has other major disadvantageous.
Another way of proceeding is to integrate the print pickup directly in the circuit of the card. A major manufacturer of integrated circuits has recently put a circuit on the market that is capable of acquiring a digital print by means of micropickups for pressure and of processing the information by extracting a datum that is characteristic of the print from it. But acquiring the furrows in, a fingerprint is done on a large surface area, on the order of a square centimeter; thus the pickup must be at least as long as one centimeter. Such a size is an obstacle to embedding such a circuit in a card, because a chip card is necessarily subjected to pronounced bending.
A first object of the present invention is to be capable of performing biometric print recognition, preventing fraud and the mechanical problems described above.
A second object of the invention is to provide a print acquisition surface which is personal to the card holder, in such a way that on an associated print acquisition appliance, no trace whatever capable of being detected remains.
A third object of the invention is to furnish means for transmitting an image to a screen that is properly visible only to one or more specific observers who hold the above defined rights.
A fourth object of the invention is to furnish identification means associated with an image projected on a screen by defining an identifier of a person who is authorized to see that image, or a portable object held by that person and by means of which the image is projected.
To this end, the invention relates to a method for producing a predetermined image by means of a device and a portable object, the device including data processing means, data memorizing means, and image processing means, and the portable object including data processing means, data memorizing means, a through window, and display means capable of displaying an image in the window, characterized in that it includes the steps comprising:
placing said window of the portable object before the image processing means of the device in such a way that they cooperate optically with one another;
producing a first image in said window;
causing a second portable object image to be displayed by the display means of the portable object; and
obtaining said predetermined image by superposition of the first image and the second portable object image.